Which group of athletes is more abnormal in height?

June 4, 2012 8:19 AM

Which group of athletes is further from the center of the bell curve distribution for height: Olympic gymnasts or NBA players?
posted by Trurl to sports, hobbies, & recreation (7 answers total)

I should have specified...

The average height of female Olympic gymnasts compared to the average height of all women, versus the average height of NBA players compared to the average height of all men.
posted by Trurl at 8:22 AM on June 4, 2012

Average height female gymnast 5'1"
Average height adult female 5' 4"

Average height NBA player: 6' 6.98"
Average height US male: 5' 9.5"

So I would say that NBA players are farther from the norm than gymnasts.
posted by LittleMy at 8:36 AM on June 4, 2012 [3 favorites]

Average height of U.S. female Olympic gymnasts was 60.5 inches. Average height of an NBA player: 79 inches.

According to this chart, the 5th percentile for women aged 15-20 is roughly 61 inches. Whereas according to this chart, the 95th percentile is around 74 inches. (These charts are by race but other races did not differ notably). So NBA players are more extreme than gymnasts.
posted by acidic at 8:47 AM on June 4, 2012 [3 favorites]

I've never been able to find these data for people over 20, although I can't say I've ever really looked that hard, but from the CDC website from which growth charts are derived:

To obtain the z-score (Z) and corresponding percentile for a given measurement (X), use the following equation:

((X/M)**L) - 1
Z = -------------------------, L≠0
LS

or

Z = ln(X/M)/S ,L=0

where X is the physical measurement (e.g. weight, length, head circumference, stature or calculated BMI value) and L, M and S are the values from the appropriate table corresponding to the age in months of the child (or length/stature). (X/M)**L means raising the quantity (X/M) to the Lth power.

For the oldest males they have (these data are in table 7), 240 months or 20 years, M=176.849, L=1.167, and S=0.04036. Using LittleMy's height, 78.98" x 2.54 cm/inch = 200.61 cm. This would be 3.36 standard deviations above the mean, assuming I calculated it correctly.

Gymnasts are trickier, since they are often younger and might grow a few inches in the future, but again using LittleMy's heights, 61" = 154.94 cm. For 20 year old women, L = 1.1080, M=163.338, S=0.0396, so gymnasts are 1.294 standard deviations below the female mean.

Hopefully I didn't calculate wrong, but I think the above posters are correct that NBA players are significantly more extreme height-wise than gymnasts.
posted by dsfan at 10:46 AM on June 4, 2012 [1 favorite]

NBA players are from all over the world, so you need to use the average male height for all countries, right? That appears to be 5'7, so the conclusion is still the same.
posted by cashman at 12:49 PM on June 4, 2012

The thing is though, that --- like dsfan mentions --- the gymnasts are often around 14/15 years old, and possibly have not reached their full adult height. To make a fair comparision, you'd have to consider both the gymnasts and the NBA players at the same ages: both groups at age 25, for instance, after both groups are likely to have reached their full growth. (Males often reach their full height at a later age than females, so a test at age 15 or even 20 would not necessarily be at the males' final height.)
posted by easily confused at 5:44 PM on June 4, 2012

Forgot to mention that official NBA heights (from which I assume the averages mentioned above are derived) are with shoes on, and they're frequently inflated. At the Portsmouth Invitational, a program for borderline NBA prospects in their senior year, players' heights were measured barefoot, then increased by an inch (for the typical shoe) and rounded to the nearest inch. Apparently 76% were inflating their heights by at least an inch. Still, though, they're more tall than gymnasts are short.

And although easily confused makes a good point that gymnasts have not reached their full adult height, the Olympic age cutoff is 16, not 14, and plenty of young NBA players are still growing too. Plus, assuming that gymnasts are likely to continue growing, that merely proves the point that NBA players are more of an extreme.
posted by acidic at 10:40 PM on June 4, 2012